Proportional scaling instrument



atented July i8? N22i,

J. D. CARTER. PROPORTIGNAL SGALING INSTRUMENT.

APPLICATION FILED FEB. 11, i921.

JAMES D. CARTER, 0F CHICAGO, ILLINOIS.

PROPGRTIONAL SCALENG INSTRUMENT.

Specification of Letters Patent.

Patented Jarvis, 1922.

Application filed February l1, 1921. Serial No. 444,131.

To all whom t may concern.'

it known that l, JAMES D. CARTER, a citizen oi the United States,residing at Chixago, in. the county of Cook and State of illinois, haveinvented certain new and useiul -linprovements in Proportional Scalingu.instVui'nents,V oiE which the following is a specilication. y

rlhis invention` relates to a scaling instrument primarily designed Jfordrafting purposes, although the mechanism shown is equally adapted toruse in connection with machinery or tools sed tor engraving, routing,carving, or other operation which requires the employment of amultiplicity of marking or cutting tools adapted to operate vin unisonand in a space ratio with one another.

The primary object of the invention is to provide a mounting for suchtools or instruments, together with suitable adjustment mechanism, sothat the several tools may be simultL neously adjusted to differentpositions without altering the spacial ratio between the respectivetools or instruments, thereby at all times maintaining a predeterminedspacial ratio irrespective of the scale chosen for the operations. Theinvention is one which permits the several too-ls or instruments to beindividually adjusted to the desired ratio with respect to one another,and thereafter permits the entire series of tools to be adjusted as agroup to any scale desired without interfering with the space ratio ofthe individual units. This arrangement permits the use oit a masterpattern of given size to be employed as a guide for the scalingtherefrom oft one or more copies drawn to a different scale, and thedevice illustrated is usable under any conditions where such a scheineot operations is required.

'lin the 'torni shown Yfor purposes oit exemplilication, the device isillustrated as a drafting instrument. but it is obvious that the markingmints shown might be replaced by carving or cutting instruments,actuated by power, ii desired, without in any way alizering themechanism employed for maintaining the ratio between the parts.

The invention consists inthe features ot construttion and combinationsof parts hereinafter described and claimed.

In the drawings:

Figure l is a side elevation of the device;

Fig. 2 is a plan View of the same;

Fig. 3 is a cross sectional, view of 4the swivel head; i

Fig. e is a cross sectional view of one of the riders and associatedkparts;

l? ig. 5 is an end view of one of they riders; undr l Fig. 6 is asectional detail oit the mounting lor the s'wiveled head.

The device comprises a pair of parallel guii'le rails i0 and ll unitedat the outer end by a cross head l2. The guide rails and cross head arepreferably formed of a stili steel rod bent to the requiredconfiguration, and the inner ends of the rails are preferably soclretedwithin upper andlower parallel socket holes in `a swiveled head 13,which, as shown, is of generally rectangular formationu The ends of theguide rods may be brazed or otherwise permanently secured in placewithin the head, although it is preferred to provide means whereby'these parts may be disassembled. As shown suoli means comprise aclamping plate l-t which is entered within a 'vertically arranged recessl5 in the swiveled head. The clamping plate, as shown in Fig. 3, isarranged to bear against the sides of the guide rods, and a threadedstem 1G is provided which extends freely through the clamping plate, andis threaded at its outer end to receive. a thumb nut l? which bearsagainst the clamping plate, so that-a turning of the thumb nut will drawthe latter tightly in contact with the contiguous portions of the upperand lower rails, thereby clamping the same tightly in position.

rlhe swiveled head is mounted upon a post i8, which, at its lower end,`carries a cross trunnion i9, the ends of which are socleted within arecessed swiveled plate 2() which is n free to rotate within a recessedbase plate 2l` shown in Fig. Gp The cross trunnion 19 is disposed intransverse'relation to the guide trame, sothat the latter may be raisedand lowered, or turned around the axis oi the swiveled post 1.8 as acenter, but is held against 'tipping or tilting in a sidewise direction.

rlhe swiveled head i3 co-operates with a slidably mounted outer head 22which rides upon the upper and lower guide rails, and is provided with aclamping plate 23 and a thumb nut 24 similar to those ypreviouslydescribed. The outer head 22 ca ries a marker which, however, mayobviously be replaced by a stylus, drill, router or other drill orinstrument, these parts being removable by the loosening oi a set screw25a or the like. v

Between the swiveled head and the outer head is mounted an elasticadjusting element 26 which, in the torni shown, consists preterably of acoiled spring ot uniform tension throughout. ills shoxvn, the ends otthe coiled spring are ixedly secured to the swiveled head and outer headrespectively, so that the latter may be adjusted to varying positionsupon the guide trame rand atterwards clamped in position by means of thethumb nut 2li, thereby expanding the elastic element--spring or thelikef-to a greater or less degree ot expansion. :is shown, the ends oinvthe spring are threaded onto socket holes 26 and 27 1n the oppositelydisposed heads which affords a convenient and satisfactory method otsecuring these arts together, although obviously other suitable orconvenient means might be provided tor securing the parts together.

Between the tivo heads are mounted one or more riders 98, tivo beingshoivn for purposes of illustration, Which riders are provided Withupper and loiver guide holes 29 and BO through which the guide rods eX-tend, the arrangement being one 'which permits the riders to slidesmoothly and evenly along the guide rods Without cramping or binding,and at the same time serves to maintain the riders against vibration ordisplacement when brought to the intended position. Each ot the ridersis provided with means 'lor clamping the same securely to the elasticelement, a suitable and convenient 'form being shown for purposes otillustration. As shown` each ot' the riders provided through its centerwith a hole or bore Ell ot' a size to permit the spring or other elasticelement to pass therethrough and the rider is also provided on itsinterior ivith a recess 32 within which is housed a split springclamping ring which embraces the coiled spring or other elastic element,the tree ends oit the split spring ring havingl entered therethrough adraw stem 34 threaded at its outer end and provided with a thumb nut 35adapted to dran1 the tree ends olf the split spring ring together, so asto tightly clamp the parts together. The split spring clamping ringbeing closely housed Within the recess in the rider will prevent any'tore and att movement oii the parts when clamped together.

ln order to more eilectively prevent any accidental movement ot' theparts, means are provided tor clamping the rider onto the rails of theguide trame. and a convenient means i'or this purpose consists ot aplate 36 provided with inwardly extending clamping lingers BT which bearagainst the upper and lovver guide rails and are adapted to be aeeaeesbrought into clamping engagement therewith by means ot a thumb nut 38threaded onto a stem 39, vchich latter passes treely through theclamping plate 36 and is threaded or otherwise rigidly entered into thecontiguous vfall ol the rider. Each ot the rriders is provided with amarking tool e0 or other requisite tool or instrument depending upon theuse for which the device is intended.

ln use, one or more riders can be mounted in position upon the guiderails by removing the lat" trom the svviveled head and passing theriders onto the rails and spring, atter which the ends ot the rails areentered and clamped within the svviveled head. Assuming that tivo ridersare to be employed, the same will be adjusted to the desired positions,so that the intended space ratio ot the several marking or cuttinginstruments will be established, after which the riders will be tightlyclamped to the coiled spring or other elastic. element by tightening theclamping ring or rings rlfhereatter the entire series may be adjusted asa unit by moving the outer head to the desired position, and this ivillresult in automatically repositioning` the riders without disturbing thespace ratio between the several parts, since each portion oi" theelastic element will elvgand or contract in unii'orm ratio `with everyother portion. lt is thus evident that it an initial adjustmento'ftheparts in the ratio oit 2. l and 6 inches trom the pivot point beestablished, and it thereafter the outer head be moved to the distanceot l2 inches .trom the pivot point, the riders will automatically assumepositions in the ratio ot l and 8 inches troni the pivot point Vwithoutindividual zidjustnient, and Without the necessity for making individualcomputations contormable to the newly established scale ot operations.

The instrument can `be readily used 'for drafting purposes` vvhereconcentric circles are to be drawn in given ratio 'to oneanother,irrespcctive ot the scale chosen, since valter the space ratioot the parts is once established.. the outer head can be adjusted to anyradius desired, and the established ratio ot the smaller circles vvillbe maintained. ln like manner, the instrument can be used tor producingplurality ot' similar figures di'ltering in scale from a master ligureorpattern, or for like operations on the drafting board, and can also beemployed tor like purposes on carving machinery, engraving n'iachinery,or Vtor other purposes of like character.

The principle ot this invention is one 'which lends itselt readily foruse in computing instruments in which visual indication rather thaninscribed lines are adequate to give the desired data. Yit' so used itis evident that the fixed portions of the device nould be suitablyscaled or marked in con- Iormity with the system of measurements hosenfor purposes of computation as indicated on the top guide rail in Figs.l and 2.

Although the invention has been described with considerableparticularity as to detail, it will be understood that the details ofconstruction may be varied or modified without departing from the spiritof the invention. I claim:

i. In an instrument of the class described, the combination of a frame,a longitudinally extensible and contractible elastic element, relativelyadjustable members carried by the frame to each of Which the elasticelement is secured, an element intermediate the relatively adjustablemembers and secured to the elastic element, and Working instruments oneof which is attached to one of the adjustable elements, and one of whichis attached to the intermediate element, for the purposes set forth.

2. ln an instrument of the class described, the combination of a guideframe, an element lined to the frame, an element slidably adjustable onthe frame, an elastic element secured to the fixed and adjustableelements, an element intermediate the fixed adjustable c elements andslidably mounted on the guide trame, and means operable from the side ofthe instrument for securing the intermediate element to the elasticelement in a predetermined spacial ratio between the fixed andadjustable elements, for the purposes set forth. l

3. ln an instrument of the class described, the combination of aguidevvay, an element fixed on the guideway, a swiveled mountingfor thefixed element, an element adjustable on the puideway, an elastic elementsecured to the fixed and adjustable elements, a rider intermediate thetwo elements and slidably mounted on the lguidevvay, means for clamping`the rider to the elastic element in any desired position of adjustment,and Working instruments carried by the adjustable element and the riderrespectively, for the purposes set forth.

Ll.. ln an instrument of the class described, the combination of aguideway, an element fixed on the gjuideway, an element adjustable outhe `guidewajg an elastic element secured to the fixed and movableelements, a rider `upon the guide rails and adjustable-to any desiredposition, an elastic element connecting the head and movable element,means for clamping the movable element in adjusted position upon the`guide rails, a rider slidably mounted upon the guide rails, means forclampingthe rider to the elastic element in any desired position ofadjustment, means for clamping the rider to the guide rails, and Workingtools carried by the movable element and rider, for the purposes setforth.

6. ln an instrument ofthe class described, the combination of a bead, aswiveled mounting` therefor, parallel upper and lower guide railscarried by the head, a' movable element slidable upon the guide rails,means for clamping the movable element upon the guide rails, a. uniformelastic element connecting the head and movable element and lying withinthe space between the guide rails, a rider slidably mounted upon theguide rails, means for clamping the rider to the elastic element in anydesired position of adjustment, means for clamping the rider to theguide rails, and Working tools carried by the movable element and therider, for the purposes set forth. f

7. ln an instrument of the class described, the combination of a head, aswiveled mounting` therefor, parallel upper and lower guide railscarried by the head, a movable element' slidable upon the guide rails,means for clamping the movable element upon the guide rails, a uniformlyelastic element connecting the head and movable element and lying'Within the space between the guide rails, a rider slidably mounted uponthe guide rails, means for clamping the rider to the elastic element inany desired position of adjustment, and Workin@` tools carried by themovable element and the rider, for the purposes set forth.

JAMES D. CARTER.

